Heres a tip I came across while making my LOMAC movie.
If you use fraps you will probably know it slows any game down a long way. What you need to do is slow the simulation down to half speed then record with fraps.
This will record at about 15 FPS on my PC anyway. Then when you come to edit your video just play the clip back at double speed and the frame rate will double to in my case 30FPS and this will give super smooth video.
Something you might like to know.
Thanks
Paul2k10